Mold assembly using inserts

ABSTRACT

An injection molding machine is provided, including a nozzle assembly having a channel for conveying a fluid. At least one cavity insert is removably mounted within a cavity plate, the at least one cavity insert defining a mold cavity, and a first portion of a gate for communicating the fluid between the nozzle assembly and the mold cavity. A gate insert defines a receptacle for the nozzle assembly, and further defining a second portion of the gate. The gate insert is floatably retained between the nozzle assembly and the at least one cavity insert. Preferably, the gate insert is retained by a gate insert plate that is disposed between the cavity plate and the nozzle assembly.

FIELD OF THE INVENTION

The present invention relates, generally, to injection molding systems.More particularly, the invention relates to the interface betweeninserts in a molding assembly.

BACKGROUND OF THE INVENTION

Injection molding is a commonly employed manufacturing technique forforming articles. An example of an article that is typically formedusing injection molding is a plastic preform. A plastic preform can thenbe subsequently blow-molded into a plastic bottle.

An injection mold for making preforms (and other molded articles)typically includes one or more molding cavities for receiving moltenresin and forming the preforms. To increase the flexibility of themolding assembly, interchangeable inserts can be inserted into bores ina cavity plate. FIG. 1 shows a portion of a prior art injection moldingmachine 10. One or more mold cavities 12 are usually defined betweencomplementary shaped, generally cylindrical cavity inserts 14 and coreinserts 15 that are arranged within bores in a cavity plate 16. The moldcavities 12 are aligned generally parallel to the direction ofmold-clamping action (i.e., the mold-clamping axis).

For mold articles that have threaded neck portions, a split neck ring(not shown) cooperates with the core insert 15 to create the neck. Ataper is typically provided at an end of the cavity insert 14 (also notshown) to help align the neck ring.

A hot runner assembly 18 communicates a flow of molten resin to meltchannels 19 in one or more nozzle assemblies 20. A gate insert 22 isseated within the mold cavity inserts 14. A first profiled surface 24 ongate insert 22 defines a receptacle to house the tip of the nozzleassembly 20. A second profiled surface 26 on the gate insert 22 definesa portion of the mold cavity 12. A gate 28 is provided in gate insert 22which provides fluid communication between the nozzle assemblies 20 andeach of the mold cavities 12. Gate 28 is open or closed by a pistonvalve 29. Other types of gating, such as slide valves or thermal gatingcan also be used

The molten resin that is injected into the cavities must be cooled tosolidify the resin so that the molded preform can be removed from themold. It is desirable to cool the preform as quickly as possible so thepreforms can be removed and a next injection cycle initiated withminimal time delay. To this effect, cooling channels 30 are typicallyprovided in the cavity and gate inserts 14 and 22. A cooling fluid, suchas water, is circulated through the cooling channels 30.

The use of mold cavity inserts 14 and gate inserts 22 increases themachine's flexibility, as the inserts can be switched to produce adifferent molded object without the need to remove the cavity plate 16from the molding assembly 10. However, before the cavity inserts 14 andgate inserts 22 can be safely removed, the nozzle assemblies 20, whichmay contain still-hot molten resin, must be allowed to cool.

Efforts have been made to improve mold assemblies. U.S. Pat. No.6,398,542 to Romanski et al. teaches a valve gating apparatus forinjection molding including at least one shutter disposed between thegate and the cavity melt channel into a mold cavity. The shutter isremovably fastened to a rail member. When the rail member is movedlaterally, the shutter moves between a closed position wherein flow ofmelt from the nozzle into the cavity is inhibited, and an open positionwherein flow of melt into the cavity is unimpeded by the shutter. In apreferred embodiment, a sliding gate valve with inserts that includes ahot runner insert around the injection nozzle and a gate insert whichdefines a portion of the mold cavity. The gate between the injectionnozzle and the mold cavity is defined and split between the hot runnerinsert and the gate insert. The hot runner insert is retained by themanifold plate of the hot runner assembly, and the gate insert isretained by the cavity plate.

U.S. patent application 2006/0099295 to Elliot teaches a gate insert fora stack assembly in an injection molding machine having a gate throughwhich a melt of thermoplastics material enters a mold cavity. The gateinsert has a cooling channel surrounding, and substantially uniformlyspaced from, the gate. The cooling channel has an inner surface with aprofile substantially parallel to the gate. The cooling channel isfurther defined by a two-piece gate insert having interconnectingsurfaces.

U.S. patent application 2005/0236725 to Niewels et al. teaches a methodand apparatus for controlling an injection mold having a first surfaceand a second surface includes an active material element configured tobe disposed between the first surface and a second surface. The activematerial element may be configured to sense a force between the firstsurface and the second surface, and to generate corresponding sensesignals. Transmission structure is coupled to the active materialelement and is configured to carry the sense signals. Preferably, anactive material element actuator is also disposed between the firstsurface and a second surface, and is configured to provide an expansiveforce between the first surface and a second surface in accordance withthe sense signals. The method and apparatus may be used to counterundesired deflection and/or misalignment in an injection mold. Theactive material actuator is operable to “tilt” a core element whenmisalignment occurs.

U.S. Pat. No. 5,736,173 to Wright et al. teaches a preform injectionmould includes an elongate mould core cooperating with a female mouldand a neck ring in a manner to define a mould cavity therebetween. Aninjection nozzle in the female mould allows molten plastic to beinjected into the mould cavity so that a preform molded article may beformed. The neck ring is constituted by a pair of mating halves whichcan be separated laterally with respect to the longitudinal axis of themould core. A taper sleeve surrounds the mould core beneath the neckring. The neck ring halves are secured to diametrically opposed slidesto facilitate lateral separation of the neck ring. A pair of slide taperlocks contact a respective one of the slides to inhibit lateral movementof the slides and to back up the neck ring when injection mould is in amould closed position. An annular formation is formed on the uppersurface of the neck ring and is accommodated by a complementary recessformed in the bottom of the female mould. The mating inclined surfacesof the female mould and the annular formation constitute an upper taperlock which is backed up by a cavity plate. An annular formation isprovided on the upper surface of the taper sleeve and is accommodated bya complimentary recess formed in the bottom of the neck ring. The matinginclined surfaces of the taper sleeve and neck ring constitute a lowertaper lock. Since a portion of the neck ring constitutes the femaletaper of the lower taper lock, the lower taper lock is backed up by theslide taper locks through the slides allowing the cross-sectional areaof the neck ring to be reduced.

U.S. Pat. No. 6,569,370 to Amin et al. teaches an injection moldingsystem for molding a molded article and method for forming same,including a mold cavity for forming the molded article, wherein the moldcavity is defined at least in part by a mold core defining inner wallsof the molded article, a first insert defining at least outer side wallsof the molded article, and a second insert defining an outer wall of aneck of the molded article. In addition, a cavity plate at least partlysurrounds the first insert and a cavity flange retains the first insertin the cavity plate.

SUMMARY OF THE INVENTION

According to a first broad aspect of the invention, there is provided aninjection molding machine, including a nozzle assembly having a channelfor conveying a fluid. At least one cavity insert is removably mountedwithin a cavity plate, the at least one cavity insert defining a moldcavity, and a first portion of a gate for communicating the fluidbetween the nozzle assembly and the mold cavity. A gate insert defines areceptacle for the nozzle assembly, and further defining a secondportion of the gate. The gate insert is floatably retained between thenozzle assembly and the at least one cavity insert.

According to a second broad aspect of the invention, there is provided amold assembly for an injection molding machine having a stationaryportion and a moving portion, and a nozzle assembly for conveying afluid. A mold cavity is defined by at least one cavity insert on thestationary portion. A mold core is defined on the moving portion. A gateinsert is floatably retained on the stationary portion between the atleast one cavity insert and the nozzle assembly and providing areceptacle for the nozzle assembly. A first portion of a gate forcommunicating the fluid between the nozzle assembly and the mold cavityis defined within the gate insert and a second portion of the gate isdefined within the at least one cavity insert.

According to a third broad aspect of the invention, there is provided agate insert plate for an injection molding machine having a nozzleassembly and a mold cavity. The gate insert plate is located between thenozzle assembly and the mold cavity. The gate insert plate includes abore for coaxially seating a gate insert which defines a gate for fluidcommunication between the nozzle assembly of the injection moldingmachine and the mold cavity.

According to a fourth broad aspect of the invention, there is provided agate for fluid communication between a nozzle assembly of an injectionmolding machine and at least one cavity insert defining a mold cavity.The gate has a first portion defined by a gate insert that is floatablyretained between the nozzle assembly and the at least one cavity insertand a second portion defined by the at least one cavity insert.

According to a fifth broad aspect of the invention, there is provided agate insert defining a receptacle for a nozzle assembly of an injectionmolding machine and further defining a portion of a gate for fluidcommunication between the nozzle assembly of the injection moldingmachine and a mold cavity. The gate insert is retained by a gate insertplate that is disposed between the mold cavity and the nozzle assembly.

According to a sixth broad aspect of the invention, there is provided aninjection molding machine. The injection molding machine includes anozzle assembly having a channel for conveying a fluid. At least onecavity insert is removably mounted within a cavity plate, the at leastone cavity insert defining a mold cavity and a first portion of a gatefor communicating the fluid between the nozzle assembly and the moldcavity. A gate insert defines a receptacle for the nozzle assembly, andfurther defining a second portion of the gate. The gate insert isretained by a gate insert plate that is disposed between the cavityplate and the nozzle assembly.

According to a seventh broad aspect of the invention, there is provideda mold assembly for an injection molding machine having a stationaryportion and a moving portion, and a nozzle assembly for conveying afluid. The mold assembly includes a mold cavity being defined by atleast one cavity insert on the stationary portion, and a mold core beingdefined on the moving portion. A gate insert is retained on thestationary portion by a gate insert plate between the at least onecavity insert and the nozzle assembly and providing a receptacle for thenozzle assembly. A first portion of a gate for communicating the fluidbetween the nozzle assembly and the mold cavity is defined within thegate insert and a second portion of the gate is defined within the atleast one cavity insert.

DETAILED DESCRIPTION OF DRAWINGS

Objects and advantages of the present invention will become apparent tothose skilled in the art upon reading the following detailed descriptionof non-limiting embodiments of the present invention, in conjunctionwith the accompanying drawings, wherein like reference numerals havebeen used to designate like elements, and wherein:

FIG. 1 shows a cross section view of a stationary portion of a prior artinjection molding machine;

FIG. 2 shows a perspective view of a stationary portion of an injectionmolding machine in accordance with a first non-limiting embodiment ofthe invention;

FIG. 3 shows a first cross section view of the stationary portion shownin FIG. 2;

FIG. 4 shows a second cross section view of the stationary portion shownin FIG. 2;

FIG. 5 shows a front plan view of a gate insert plate for the stationaryportion shown in FIG. 2;

FIG. 6 shows a cross section view of a cavity insert plate for thestationary portion shown in FIG. 2;

FIG. 7 shows a cross section view of a portion of a core insert platefor a moving portion of a hot runner assembly;

FIG. 8 shows a perspective view of a taper insert plate for thestationary portion shown in FIG. 2;

FIG. 9 shows a cross section view of a cavity insert plate for thestationary portion shown in FIG. 2, in accordance with a secondnon-limiting embodiment of the invention;

FIG. 10 shows a cross section view of a gate insert for the stationaryportion shown in FIG. 2, in accordance with a third non-limitingembodiment of the invention; and

FIG. 11 shows a cross section view of a cavity insert plate for thestationary portion shown in FIG. 2, in accordance with a fourthnon-limiting embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIGS. 2-4, a stationary portion of a multi-cavity injectionmolding machine in accordance with a first non-limiting embodiment ofthe invention is shown generally at 40. The stationary portion 40includes a manifold backing plate 42, a manifold plate 44, a gate insertplate 46, a cavity plate 48 and a taper insert plate 50.

A hot runner system 52 is provided within stationary portion 40 whichprovides a fluid, typically molten resin to one or more nozzleassemblies 54 that are distributed across the system. The implementationof the nozzle assemblies 54 is not particularly limited and can includeboth thermal gated and valve gated nozzle assemblies. It is contemplatedthat the present invention is particularly suited to, but notnecessarily limited to, injection molding machines that producepolyethylene teraphthalate (PET) preforms. The molten resin is suppliedto hot runner system 52 from a resin source, typically a hopper feedingresin pellets to a plasticizer (not shown) and thence to a main meltchannel 56. Main melt channel 56 conveys the now molten resin to themanifold 57. As is well known, the manifold 57 has a number of manifoldmelt channels 58 through which the molten resin travels to nozzleassemblies 54 while it is maintained at an optimum processingtemperature by manifold heaters 60.

Each of the nozzle assemblies 54 is coaxially located within a bore 62provided in the manifold plate 44, sandwiched between manifold backingplate 42 and the gate insert plate 46. Each of the nozzle assemblies 54generally includes a generally conical nozzle sheath 64 in which is helda nozzle tip 66 through which runs a nozzle channel 68 that is incommunication with one of the manifold melt channels 58. In thepresently illustrated embodiment, nozzle assemblies 54 are valve gated.A valve stem 70 is operable to be reciprocated by a piston 72 between anopened and a closed position. In the open position, resin exits each ofthe nozzle assemblies 54 through nozzle tip 66 and out through a gate 74(best seen in FIG. 6 and described in greater detail below). In theclosed position (as shown in FIG. 3), valve stem 70 closes off gate 74,preventing the resin from exiting through the nozzle tip 66. A nozzleheater 76 maintains nozzle tip 66 at a relatively high temperature,determined by the molten resin being injected. However, the invention isnot particularly limited to nozzle assemblies 54 that use valve gates,and other types of nozzle assemblies are within the scope of theinvention.

Manifold plate 44, gate insert plate 46 and cavity plate 48 are mountedand aligned together in stationary portion 40 via fasteners 78 whichextend through coaxial apertures 80 in each of the three plates. Gateinsert plate 46 is also directly mounted to manifold plate 44 viafasteners 82 which extend through coaxial apertures 84 in the twoplates. It will thus be apparent that cavity plate 48 can be removedfrom stationary portion 40 without removing gate insert plate 46 fromthe manifold plate 44.

Referring now to FIGS. 5 and 6, in addition to FIG. 3, distributedacross gate insert plate 46 are a plurality of gate bores 86 that arecoaxially aligned with nozzle assemblies 54 (and thus generally alignedwith the axis of mold clamping). Each of the gate bores 86 is adapted toreceive a gate insert 88. Each of the gate bores 86 narrows to provide agate land 89 which supports a flange 90 on the gate insert 88 in orderto retain the gate insert in a “floating” fit so that the gate insert 88can slide along a plane generally traverse to the mold-clamping axis.When properly seated in its respective gate bore 86, the gate insert 88is recessed fully within the plane of the gate insert plate 46. Aprofiled surface 91 within gate insert 88 defines a receptacle for thenozzle sheath 64. The profiled surface 91 is complementary to nozzlesheath 64, thereby substantially and coaxially aligning each of thenozzle assemblies 54 with their respective gate insert 88. As is knownto those of skill in the art, a gate insert 88 can be replaced by therepeated wear and tear of opening and closing of gate 74. If desired,profiled surface 91 can be lined with an insulating material to reduceunwanted heat transference from the nozzle assemblies 54 to gate insertplate 46.

A first portion of the gate 74 is defined with gate insert 88, extendingfrom the tip of profiled surface 91 in gate insert 88 towards a moldcavity 92 located within cavity plate 48. Gate 74 is in communicationwith both the nozzle channel 68 and mold cavity 92, thereby permittingthe flow of molten resin from the first to the latter. Since the gateinsert 88 is retained by the gate insert plate 46, the gate insert 88covers the nozzle assembly 54 even when the cavity plate 48 is removed.

The mold cavity 92, which defines an exterior surface of a molded objectsuch as a preform (not shown), is generally defined by at least onecavity insert, and specifically in the currently illustrated embodimentby a first cavity insert 100 and a second cavity insert 102. Each firstcavity insert 100 is retained within a cavity bore 101 in cavity plate48. An insert land portion 103 of cavity bore 101 prevents first cavityinsert 100 from exiting out of the cavity plate 48 in a non-preferreddirection. Second cavity insert 102 is coaxial with the first cavityinsert 100 and seated on an insert land 105 on first cavity insert 100.It will be apparent from the figures that a first portion of gate 74 isdefined by gate insert 88 and that a second portion of gate 74 isdefined by first cavity insert 100. Gate insert 88 and first cavityinsert 100 float relative to one another on an axis generally traverseto the mold clamping axis, providing a sliding, or “floating” interfacebetween the two halves of gate 74.

Cooling channels 104 are typically provided in first cavity insert 100to cool the resin injected into the mold cavity 92. In addition, acooling channel 106 is defined in a gap between the second cavity insert102 and cavity plate 48. Cooling channel 106 is operable to receive acooling mold cavity insert (not shown), as is described in pending U.S.application Ser. No. 11/254,325, entitled “Molding Insert with a CoolingChannel Insert”, and filed on Oct. 20, 2005. A cooling fluid, such aswater is circulated through the cooling channels 104 and 106 (via themold cavity insert) during a cooling phase of an injection cycle, aswill be further described below. Referring in addition to FIG. 2, thecooling fluid enters the cavity plate 48 through inlet 108 and is routedto cooling channels 104 and 106 via transport channels 111 (FIG. 3) inthe cavity plate 48. After completing its circuit, the cooling fluidexits cavity insert plate the through outlet 112. Seal niches 114 areprovided to locate rubberized seals and prevent leakage between firstcavity inserts 100 and second cavity inserts 102.

Referring now to FIG. 7, a portion of a moving portion 116 for aninjection molding machine is shown. A core member 118 is mounted to acore plate 119 via fasteners 121. Core member 118 cooperates with firstcavity insert 100 and second cavity insert 102 to define the mold cavity92. Core member 118 defines a mold core, shaping the inner surface ofthe preform. A core taper 120 is provided on core member 118 to helpalign core member 118 with mold cavity 92 during closure of the two moldhalves. Core member 118 includes a cooling tube 122 to cool the interiorsurface of the preform. A cooling fluid, such as water is circulatedthrough the cooling tube 122 during a cooling phase of an injectioncycle, as will be further described below. The cooling fluid is routedto cooling tube 122 via transport channels 125 in the core plate 119.The cooling water then runs down the annular tube 127 and issubsequently removed from core plate 119 out through return channel 129.

Referring back to FIG. 6, and additionally to FIG. 8, taper insert plate50 insert is mounted to cavity plate 48 via fasteners 123 which extendthrough coaxial apertures 124 in both of the plates. Distributed acrosstaper insert plate 50 are a plurality of taper insert bores 126 that arecoaxially aligned with the mold axis defined by nozzle assemblies 54.Each of the taper insert bores 126 is adapted to receive a taper insert128. Taper insert 128 retains the second cavity insert 102 within itscavity bore 101, and is in turn, retained by taper insert plate 50. Eachtaper insert 128 includes a cavity plate land 130 which abuts againstcavity plate 48, a cavity insert land 132 which abuts against the secondcavity insert 102, and a taper plate land 134 which abuts against taperinsert plate 50, thereby retaining the taper insert 128 in a floatingfit between taper insert plate 50 and second cavity insert 102. Inaddition, first cavity insert 100 and second cavity insert 102 now floatbetween gate insert 88 and taper insert 128 along an axis generallytraverse to the mold-clamping axis.

When properly seated in its respective taper insert bore 126, the taperinsert 128 is recessed fully within the plane of the taper insert plate50. Taper insert 128 further includes a tapered surface 136 which helpslocate a neck ring (not shown) during the insertion of the core member118 into the mold cavity 92 during the injection cycle. A seal niche 138is provided to locate a rubberized seal 139 and prevent leakage betweentaper insert 128 and cavity plate 48.

Referring now to FIG. 9, a stationary portion of a multi-cavityinjection molding machine in accordance with a second non-limitingembodiment of the invention is shown generally at 140. Stationaryportion 140 includes a gate insert plate 146, a cavity plate 148, and ataper insert plate 150. A gate insert 188 is seated within a gate bore186 in the gate insert plate 146. A first portion of a gate 174 isdefined within gate insert 188. A cooling channel 190 is defined withingate insert 188 to reduce heat transference from nozzle assembly 54(FIG. 3) to a cavity 192, which is defined between a cavity insert 200and a core member 218 which is mounted to the moving portion (notshown). In the illustrated embodiment, a cooling fluid, such as water,is circulated through the cooling channels 190 during a cooling phase ofan injection cycle, as will be further described below. The coolingfluid is routed to cooling channels 190 via transport channels (notshown) in the gate insert plate 146. An additional cooling channel 214is defined between a taper insert 228 and taper insert plate 150. Thecooling fluid is routed to cooling channel 214 via transport channels215 in the gate taper insert plate 150

The cavity insert 200 is seated within a cavity bore 201 within cavityplate 148. A second portion of gate 174 is defined within cavity insert200 that is in floating communication with the first portion of gate174. The exterior surface of the preform is defined by the single cavityinsert 200. Gate insert 188 includes a tapered portion 202, and cavityinsert 200 include a complementary tapered portion 204, to substantiallyand coaxially align the two inserts together. The interface betweentapered portion 202 and 204 allows cooling channel 190 to be locatedcloser to cavity 192, thereby increasing the cooling efficiency of thecooling channel 190.

Gate insert plate 146 includes tapered side portions 206 along asidewall 208 of gate bore 186 to reduce the force required for theinsertion of gate insert 188 into gate bore 186. In addition, a gap 210is provided between the edge of a flange 212 on gate insert 188 andsidewall 208. Given the tapering, there is minimal float for the gateinsert 188 traverse to the mold-clamping axis than in the embodimentdescribed in FIG. 6. It is contemplated that clearance could be providedbetween tapered portions 202 and 24 should a greater degree of float bedesired.

Referring now to FIG. 10, a gate insert in accordance with a thirdnon-limiting embodiment of the invention is shown at 288. A firstportion of a gate 274 is defined by gate insert 288 and a second portionof gate 74 is defined by a first cavity insert 300 (which defines aportion of a cavity 292). Gate insert 288 and first cavity insert 300float relative to one another on an axis generally traverse to the moldclamping axis, providing a sliding, or “floating” interface between thetwo halves of gate 274.

A cooling channel 290 is cooperatively defined between gate insert 288and cavity insert 300 to reduce heat transference from nozzle assembly54 to a cavity 192. A cooling fluid, such as water, is circulatedthrough the cooling channels 190 during a cooling phase of an injection.By splitting the cooling channel 290 between gate insert 288 and cavityinsert 300, the machining of the cooling channel 290 is simplified. Sealniches 314 are provided to locate rubberized seals and prevent leakageinto cavity 292.

Referring now to FIG. 11, a second cavity insert having an integraltaper is shown at 402. Second cavity insert 402 is retained at one endby a first cavity insert 100, as is described above, and is retained atthe other end by taper insert plate 50. Each second cavity insert 402includes a cavity plate land 430 which abuts against cavity plate 48,and a taper plate land 434 which abuts against taper insert plate 50,thereby retaining the second cavity insert 402 in a floating fit betweentaper insert plate 50 and first cavity insert 400. Second cavity insert402 further includes a tapered surface 436 which helps locate a neckring (not shown) during the insertion of the core member (also notshown) into the mold cavity 92 during the injection cycle. A seal niche438 is provided to locate a rubberized seal and prevent leakage betweensecond cavity insert 402 and cavity plate 48.

The operation of the present invention will now be described over thecourse of an injection cycle, with reference to FIGS. 2-3. In a typicalinjection cycle, valve stem 70 is retracted by piston 72 to open thegate 74. Molten resin, fed by hot runner system 52 to nozzle channel 68,and hence to nozzle tip 66, is conveyed under pressure to mold cavity 92through gate 74. Throughout the cycle, nozzle heaters 76 to maintainresin in nozzle channel 68 at an optimum processing temperature. Oncethe mold is full, valve stem 70 is advanced to seat in gate 74 to stopthe flow of resin. The cooling channels 104 and 106, and the coolingtube 122 circulate water to remove heat from the resin, causing it tofreeze into the shape of the preform. The mold opens and the preform isejected (not discussed). The mold then closes, and the cycle repeats.

After a number of cycles, an operator may wish to exchange the firstcavity inserts 100 and second cavity inserts 102, typically in order toprovide a different cavity shape. The operator will remove the taperinsert plate 50. Taper inserts 128 can be exchanged, if needed. Althoughnozzle assemblies 54 remain dangerously hot, the operator will be ableto slide the first cavity inserts 100 and second cavity inserts 102 outof cavity bore 101 since gate insert 88 fully covers the nozzleassembly.

Non-limiting embodiments of the present invention can decrease theamount of time required that operators must wait before exchangingcavity inserts as the nozzle assemblies remain covered by the gateinserts during the conversion. Non-limiting embodiments of the presentinvention can reduce cycle time due to cooling efficiency in the gateand taper inserts. In addition, non-limiting embodiments of the presentinvention can reduce the wear and tear on the gate and taper inserts dueto the inserts being seated in a floating arrangement. Furthermore,non-limiting embodiments of the present invention can reduce the costfor prototype stacks as the gate and taper inserts are machinedindependently of the cavity inserts.

The description of the exemplary embodiments provides examples of thepresent invention, and these examples do not limit the scope of thepresent invention. It is understood that the scope of the presentinvention is limited by the claims. The concepts described above may beadapted for specific conditions and/or functions, and may be furtherextended to a variety of other applications that are within the scope ofthe present invention. Having thus described the exemplary embodiments,it will be apparent that modifications and enhancements are possiblewithout departing from the concepts as described. Therefore, what is tobe protected by way of letters patent are limited only by the scope ofthe following claims.

1. A mold assembly for an injection molding machine having a stationary portion and a moving portion, and a nozzle assembly for conveying a fluid, comprising: a cavity plate associated with the stationary portion, the cavity plate housing a cavity insert for defining (i) a first portion of a mold cavity and (ii) a first portion of a gate for communicating the fluid; a core plate associated with the moving portion, the core plate housing a mold core, the mold core for defining a second portion of the mold cavity; a gate insert plate housing a gate insert for defining (i) a receptacle for the nozzle assembly and (ii) a second portion of the gate, the gate insert being floatably retained within the gate insert plate for allowing the gate insert to float relative to the cavity insert; whereby the gate insert and the cavity insert float relative to one another on an axis generally traverse to a mold clamping axis.
 2. The mold assembly of claim 1, wherein the gate insert plate is operable to continually cover a portion of the nozzle assembly while the at least one cavity insert is removed from the stationary portion.
 3. The mold assembly of claim 1, wherein both the gate insert plate and the nozzle assembly are mounted to a manifold plate on the stationary portion of the injection molding machine.
 4. The mold assembly of claim 2, wherein the cavity insert includes a first cavity insert and a second cavity insert that are cooperatively aligned to define the mold cavity.
 5. The mold assembly of claim 3, wherein at least one of the first cavity insert and the second cavity insert defines a cooling channel.
 6. The mold assembly of claim 2, wherein the gate insert defines a cooling channel.
 7. The mold assembly of claim 1, wherein the gate insert includes a tapered portion that is complementary to an adjacent tapered portion on the at least one cavity insert.
 8. The mold assembly of claim 7, wherein a cooling channel is located at least partially within the tapered portion.
 9. The mold assembly of claim 7, wherein an interface between the tapered portion on the gate insert and the adjacent tapered portion on the at least one cavity insert helps to align the first portion of the gate and the second portion of the gate.
 10. The injection molding machine of claim 5, wherein a cooling channel is cooperatively defined between the gate insert and one of the at least one cavity insert. 